The following relates generally to wireless communication, and more specifically to low latency operation with different hybrid automatic repeat request (HARQ) timing.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems, (e.g., a Long Term Evolution (LTE) system). A wireless multiple-access communications system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).
In some cases, a base station and a UE may operate based on a low latency physical (PHY) layer timing structure. Low latency operations (for example, operations based on a reduced transmission time interval (TTI)) may enable a reduction in the delay between a transmission and a HARQ response. However, the reduced delay may also reduce the time available for a UE to process a transmission and determine a response. For UEs with a large propagation delay (and hence, a large timing advance) this reduced processing time may not be sufficient.